Concrete surfacing apparatus



' Nov. 30, 1965 w. H. LEWIS 3,220,321

CONCRETE SURFAC ING APPARATUS Filed Aug. 28, 1962 5 Sheets-Sheet l INVENT WILLIAM HURST BY FULWIDER, PATTON,

RIEBER, LEE & UTECHT WIS TQB lL Nov. 30, 1965 w. H. LEWIS 3,220,321

CONCRETE SURFACING APPARATUS FiledAug. 28, 1962 5 Sheets-Sheet 2 FIGS INVENTOR. WILLIAM HURST LEWIS BY FULWIDER, PATTON,

RIEBER, LEE & UTECHT ATTOR NEYS Nov. 30, 1965 w. H. LEWIS 3,220,321

CONCRETE SURFACING APPARATUS Filed Aug. 28, 1962 5 Sheets-Sheet 5 INVENTOR. WILLIAM HURST LEWIS BY F ULWIDER, PATTON,

RIEBER, LEE & UTECHT ATTORNEYS United States Patent 3,220,321 CONCRETE SURFACIN G APPARATUS William Hurst Lewis, 9530 E. Rush St., El Monte, Calif. Filed Aug. 28, 1962, Ser. No. 219,890 9 Claims. (Cl. 94-45) The present invention relates to concrete surfacing apparatus, and more particularly to self-propelled means for effecting the final surfacing operation on a relatively large expanse of fluid concrete.

In order to produce the desired surface on a relatively large section of concrete, as in the formation of roadways, airport runways, flood control canals and the like, 1t has been found desirable to have a separate finishing or surfacing machine which can be used at the proper time and in the proper manner after the concrete has already been generally leveled by conventional equipment. That is, the finishing operation can be more effective if performed after the concrete has been permitted to set for a given period of time. Thus, such surfacing machine or apparatus should be self-propelled so as to be usable independently of any other paving apparatus.

In order to provide freshly laid concrete with the proper surface, the surfacing apparatus must be capable of performing many varied operations quickly and effectively. Also, such apparatus must be sufficiently strong and rugged to withstand the usual rough treatment encountered during normal use.

The present invention provides a machine for surfacing fluid concrete, such machine being self-propelled and so constructed as to be continuously operable as it moves over a given section of fluid concrete.

This invention has as one of its objects the provision of surfacing apparatus which provides the final contour and surface condition for both the top and sides of a given section of concrete.

Another object of the present invention is to provide concrete surfacing apparatus having surfacing means which can be adjusted, as desired, for varying the contour of the section of concrete.

Another object of the present invention is to provide concrete surfacing apparatus as characterized above which includes liquid spraying means for controlling the dampness of the surface of the concrete to insure proper curing.

Another object of the present invention is to provide surfacing apparatus as characterized above which is selfpropelled.

A still further object of the present invention is to provide concrete surfacing apparatus as characterized above which can be operated by a minimum number of operating personnel.

Another object of the present invention is to provide apparatus as characterized above which includes means for providing a burlap finish to the concrete surface.

Another object of the present invention is to provide apparatus as characterized above which is easy to control and operate.

Another object of the present invention is to provide apparatus as characterized above which is simple and inexpensive to manufacture, and which is rugged and dependable in operation.

The novel features which I consider characteristic of my invention are set forth with particularity in the appended claims. The device itself, however, both as to its organization and mode of operation, together with additional objects .and advantages thereof, will best be understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIGURE 1 is a perspective view of surfacing apparatus according to the present invention;

FIGURE 2 is a diagrammatic illustration of a portion of the drive means for the apparatus of FIGURE 1;

FIGURE 3 is a top plan view of the apparatus of FIG- URE 1;

FIGURE 4 is a fragmentary end elevational view taken substantially along line 4-4 of FIGURE 3;

FIGURE 5 is a side elevational view taken substantially along line 5-5 of FIGURE 3;

FIGURE 6 is a fragmentary top plan view taken substantially along line 6-6 of FIGURE 5;

FIGURE 7 is an end elevational view of the adjustable side forms of the apparatus of FIGURE 1; and

FIGURE 8 is a sectional view of the side form taken substantially along line 8-8 of FIGURE 7.

Like reference characters indicate corresponding parts throughout the several views of the drawings.

Referring to FIGURE 1 of the drawings, there is shown therein concrete surfacing apparatus 10 according to the present invention. Apparatus 10 comprises a horizontally disposed box frame 12 which is formed of side, members 14 and 16 and a plurality of transverse interconnecting members as shown at 18, 20, 22, 24 and 26. As will be readily apparent to those persons skilled in the art, the members 1426 inclusive are structural members and may have any desired cross-section to provide the necessary strength and rigidity for frame 12. That is, such members might be provided with a U-shaped cross-section as shown with respect to members 18 and 20, or they may be provided with an I-shap ed cross-section as shown at member 22.

The structural members 14-26 inclusive should be firmly welded together and suitable cross members for providing the necessary rigidity to frame 12 should also be provided. To further strengthen frame 12, it may be desirable to provide a truss on top of each of the side members 14 and 16 as shown respectively at 28 and 30.

Attached to frame 12 are wheels 32, 34, 36 and 38 for propelling the entire frame over a section of fluid concrete as will hereinafter become more apparent. As seen in the drawings, the Wheels include ground engaging portions depending below the frame. Each of such wheels, of course, is provided with an axle which is properly mounted within a housing attached to and depending from the frame as shown at 32a, 34a, 36a and 38a respectively.

A suitable platform or catwalk 40 is positioned across the structural members 20, 22 and 24 to provide a support for suitable motive power means and for an operator of the apparatus. Such catwalk might include a hand rail as shown at 42. The motive power means shown in the drawings includes an internal combustion engine 44 and suitable transmission means 46, together with appropriate manual controls therefor and a seat 48 for the operator. It is contemplated within the scope of the present invention that the motive power means for the present apparatus may take substantially any desired form of portable power.

Internal combustion engine 44 is employed for driving the aforedescribed wheels to transport frame 12 over the fluid concrete. To accomplish this, the transmission 46 is operatively connected to a drive shaft 50 which carries a drive gear 52 located within structural member 16. As shown in FIGURE 2 of the drawings, a drive chain 54 cooperates with drive gear 52 and a pair of intermediate gears 56 and 58 which are rotatably mounted within the opposite ends of member 16 immediately above wheels 32 and 34 respectively. Gear member 56 is employed for driving wheel 32 through an endless chain 60 and a drive gear 62, the latter of which is keyed to the axle of wheel 32. Chain 60 is disposed within housing 32a. Gear member 58, on the other hand, is employed to 3 drive wheel 34 through a chain 64 and a drive gear 66 which is suitably keyed to the axle of wheel 34.

A similar drive arrangement may be provided for wheels 36 and 38 on the other side of frame 12 so that all of the wheels of the apparatus are employed for transporting the frame 12 over the freshly laid concrete.

Disposed on opposite sides of the frame are individual side form structures as shown at 70 and 72. Each such structure comprises a pair of inverted T-shaped members, as shown at 74 and 76 with respect to structure 70, which are pivotally attached to structural members and 24 respectively as will be hereinafter explained. A pair of support rods 78 and 80 are connected between the horizontal portions of the T-shaped members 74 and 76 by welding, brazing or the like.

A plurality of L-shaped corner members 82, 84 and 86 are mounted in spaced relation on supporting rods 78 and 80 by suitable fastening bolts as shown most clearly at 88 and 90 in FIGURE 7 of the drawings. Such bolts extend through suitable openings in the members 78 and 80, and fastening nuts are provided for cooperation with such bolts to suitably position the corner members as desired. As shown most clearly in FIGURES 1 and 7, the leading and trailing edges of both the horizontal and vertical portions of the corner members are beveled to insure that such members provide the desired leveling action along the corner of the section of concrete being worked.

Each of the inverted T-shaped members is both rotatably and rectilinearly movable with respect to the corresponding structural member of frame 12. As shown in FIGURE 7, member 76 is telescopically fitted within a section of pipe 92 which is rotatably mounted on structural member 24. The upper end 92a of pipe 92 is closed to prevent the upper end portion of member 76 from extending therebeyond as will hereinafter appear.

To individually retract the side form structures 70 and 72 on either side of frame 12, there is provided pivotal levers 94 and 96 on structural member 24. For positioning side form structure 70, there is provided a cord or cable 98 which is attached to the horizontal portion of inverted T-shaped member 76, and a similar cable 100 which is attached to the horizontal portion of member 74. Cable 98 extends upwardly from its attachment to member 76, and is positioned on a pulley 102 secured to the upper end portion of cylindrical pipe section 92. From there, cable 98 extends directly to lever 94 for attachment thereto by a flexible chain 104.

Cable 100, on the other hand, extends upwardly and over a pulley 106 from its attachment to member 74. Such cable is then positioned on pulley 108 mounted on structural member 24. From thence the cord is attached to lever 94 through the chain 104. Thus, pivotal movement of lever 94 causes the tension in cables 98 and 100 to be simultaneously increased or decreased so as to effect corresponding movement of side form structure 70.

The cables and pulleys for retracting side form structure 72 are substantially identical with these described with respect to structure 70, and are operatively associated with lever 96 in like manner.

In operation, the cables for each side form structure operate simultaneously. As illustrated in FIGURE 7 of the drawings, upon pivotal movement of lever 94 so as to increase the tension on cables 98 and 100, the vertical rotation of each T-shaped member 74 and 76 is first moved upwardly within the corresponding tubular member. Such movement continues until the top of the vertical portion, as shown at 761) in FIGURE 7, engages the upper end of such tubular member as shown at 92a with respect to tubular member 92. By this time, the corner members 82, 84 and 86 have been removed from the concrete.

Further tightening of cables 98 and 100 causes the inverted T-shaped members 74 and 76 to be pivoted with their tubular members on structural members 20 and 24.

Since cables 98 and are actuated simultaneously by lever 94, the side form structure 70 is moved as a unit with respect to the concrete being worked. The side form structure 72, of course, operates in like manner in response to pivotal movement of lever 96.

Suspended from frame 12 is an elongated tubular surfacing member 110 which is formed of any appropriate material. As seen in FIGURE 5 of the drawings, tubular member 110 is pivotally mounted with respect to frame 12 by means of a pivot post 112 which is positioned in suitable bearing means in frame 12. A mounting bar 114 of substantially square cross-section is pivotally fastened to the lower end of post 112 by a U-shaped bracket 116 and a pivot pin .118. Such arrangement permits mounting bar 114 to pivot or rock with respect to pivot post 112 as will hereinafter become more apparent.

For supporting member 110 on bar 114, there is provided a pair of outwardly extending flexible tension members 120 and 122 as shown in FIGURE 5 of the drawings. Members 120 and 122 may take substantially any desired form such as link chains which permit considerable movement of surfacing member 110 with respect to bar 114.

At either end of mounting bar 114 is further flexible support means each of which comprises a U-shaped bracket 124 and a pair of tension members or chains 126 and 128. Each of said chains is connected to one end of U-shaped bracket 124, and to surfacing member 110 and mounting member 114 as shown in FIGURE 4.

Stiifening means is provided for surfacing member 110 to overcome the inherent flexibility of said member and to assist in providing substantially any desired shape therefor. That is, in surfacing roadways or other large sections of concrete, it is frequently desirable to provide a predetermined gradual slope from the center to the outer edges. Such contour is commonly termed a crown and is desirable for purposes of better drainage and the like. Such a crown can be provided in a long section of concrete merely by providing surfacing mem ber 110 with the proper shape throughout its length.

Such stiffening means, as shown most clearly in FIG- URE 4 of the drawings, comprises an elongated relatively inflexible member 130 which may have substantially any appropriate cross-section, as for instance a U-shaped cross-section as shown in the present embodiment. Member 130 extends the length of tubular member 110 and is supported therewithin by a plurality of fastening bolts 132 which are spaced along the length of the members 110 and 130. Each fastening bolt 132 is threaded into appropriate openings in surfacing member 110 and stiffening member 130. As such, each longitudinally spaced cross-section of surfacing member 110 can be separately and independently positioned relative to member 130. Due to this arrangement, it is possible to adjust the various fastening bolts 132 such that the intermediate portion of tubular member 110 is at a higher elevation than the ends thereof. This, of course, will cause surfacing member 110 to provide a crown for the section of concrete.

A hydraulic actuator 134 is interposed between the bracket 116 and the frame 12 for varying the angular disposition of surfacing member 110 with respect to the direction of travel of the subject surfacing apparatus. One end of actuator 134 is fastened to a mounting bracket 136 fixed to frame 12, while the other end thereof is connected to an upstanding tab 116a on bracket 116. Suitable fluid conduits 138 and 140 transmit hydraulic pressure to and from actuator 134 from a compressor driven by internal combustion engine 44-.

On opposite sides of frame 12 are fluid reservoirs or tanks and 152. Each such reservoir is supported in a raised position by suitable support means 150a and 152a respectively. These tanks are provided with water or any other appropriate fluid for spraying or dampening the surface of the section of concrete being worked. As shown at 154 with respect to reservoir 152, there is provided for each of the reservoirs 150 and 152 suitable hose means for connecting the reservoirs to separate spraying devices. At the forward end of the surfacing apparatus 10, there is provided spray means 156 and 158 each of which comprises an elongated section of pipe 156a and 158a, respectively, and a spray nozzle 156k and 158b, respectively. Extending from member 18 of frame 12 in a rearward direction are spraying devices 160 and 162 each of which comprises a section of pipe 160a and 162a, respectively, and a spray nozzle 16% and 162b, respectively. Reservoir 150 is connected to the spraying devices 156 and 160, while the reservoir 152 is connected to devices 158 and 162. Suitable valve means may be employed for controlling the distribution of fluid between the forward and rearward spraying devices associated with each reservoir as desired.

Positioned to the rear of frame 12 is a frame work 170. Such frame work comprises suitable elongated support members 170a, 170b, 1700 and 170d arranged in pairs on opposite sides of frame 12 as shown in FIG- URES 1 and 3, and which are pivotally attached to structural member 18 of frame 12. Frame work 170 also comprises a truss 1702 which includes a lower horizontal member 170 to which is attached an elongated piece of burlap 172 to be dragged over the surface of the concrete. The position of burlap 172 with respect to the concrete surface is controlled by a pair of hydraulic actuators 174 and 176 on opposite sides of frame 12. One end of actuator 174 is fastened to an upwardly extending bracket 178 while the other end thereof is connected to support member 170a. In like fashion, actuator 176 has one end firmly attached to an upwardly extending bracket 182 while the other end thereof is fixed to support member 170d. The actuators 174 and 176, of course, are supplied with fluid pressure from the aforementioned compressor driven by engine 44. Thus the burlap 172 can be lowered into engagement with the surface of the concrete, or it can be raised out of contact therewith by suitable manipulation of appropriate control means in the hydraulic lines to actuators 174 and 176.

It is thus seen that the present invention provides a self-powered surfacing apparatus for providing a smooth finish to the upper surface and side edges of an elongated section of concrete.

Although I have shown and described certain specific embodiments of my invention I am fully aware that many modifications thereof are possible. My invention, therefore, is not to be restricted except insofar as is necessitated by the prior art and by the spirit of the appended claims.

I claim:

1. An apparatus for surfacing a longitudinal section of freshly laid concrete unbounded by side forms and which has already been generally leveled by conventional means, said apparatus comprising:

a frame adapted to span said section of concrete;

means supporting said frame for location of said frame above the surface of said section of concrete and including rolling means at the sides of said frame, said rolling means including ground engaging portions depending below said frame for traction upon irregular contours of the ground or other supporting surface laterally outwardly of said concrete whereby said frame is transportable in a longitudinal direction over said concrete and out of contact therewith;

an elongated surfacing member suspended from said frame for spanning the width of said concrete, said member having a curved lower surface for surfacing said concrete; and

means suspending said member from said frame in diagonal orientation relative to the direction of transport of said frame for dragging engagement with the surface of said concrete during said transport of said frame whereby bumps and similar irregularities in said concrete are smoothed by said member and any excess concrete is conveyed diagonally along the length of said member, said last-mentioned means including separate connecting elements coupled to opposite extremities of said member, respectively, and operable independently of each other, said connecting elements being characterized by flexibility whereby said member derives its vertical orientation and support solely from floating on said concrete, and whereby purely vertical movements of said frame and differential vertical movements of said frame resulting from lateral tipping thereof are isolated from said member, and whereby vertical movements of any of said connecting elements are isolated from any other of said connecting elements during a surfacing operation.

2. Apparatus according to claim 1 wherein said connecting elements are chains.

3. Apparatus according to claim 1 wherein said means suspending said member from said frame include a rigid, elongated mounting element overlying said surfacing member in parallel relationship, and said connecting elements are constituted by a plurality of chains suspending said surfacing member from said mounting element.

4. Apparatus according to claim 1 wherein said surfacing member is tubular and the longitudinal axis thereof lies entirely within a vertical plane whereby excess or struck concrete may be conveyed diagonally along said surfacing member from the leading portion to the trailing portion thereof.

5. Apparatus according to claim 1 and including means interposed between said frame and said means suspending said member from said frame, and operative upon said last-mentioned means to vary the angle of orientation of said member relative to said frame.

6. An apparatus for surfacing a longitudinal section of freshly laid concrete unbounded by side forms and which has already been generally leveled by conventional means, said apparatus comprising:

a frame adapted to span said section of concrete;

means supporting said frame for location of said frame above the surface of said section of concrete and including rolling means at the sides of said frame, said rolling means including ground engaging pore tions depending below said frame for traction upon irregular contours of the ground or other supporting surface laterally outwardly of said concrete whereby said frame is transportable in a longitudinal direction over said concrete and out of contact therewith;

an elongated surfacing member suspended from said frame for spanning the width of said concrete, said member having a curved lower surface for surfacing said concrete;

a pivot post supported by said frame intermediate the sides thereof for pivotal movement about a vertical axis;

a rigid, elongated mounting element supported by said pivot post for pivotal movement about a horizontal axis; and

a plurality of flexible elements suspending said surfacing member from said mounting element for dragging engagement with the surface of said concrete during said transport of said frame whereby bumps and similar irregularities in said concrete are smoothed by said member, said flexible elements being coupled to opposite extremities of said surfacing member, respectively, and operable independently of each other whereby, during a surfacing operation, said member derives its vertical orientation and support solely from floating on said concrete, and whereby purely vertical movements of said frame and differential vertical movements of said frame resulting from lateral tipping thereof are isolated from said member, and whereby vertical movements of any of said flexible elements are isolated from any other of said flexible elements during a surfacing operation.

7. Apparatus according to claim 6 and including hydraulic cylinder means connected to said frame and operative upon said mounting element to pivot said mounting element and thereby vary the angle of orientation of said member relative to said frame.

8. Apparatus according to claim 6 and including a rigid member coextensive with said surfacing member, and a plurality of adjustable fastening members interconnecting said surfacing member and said rigid member at spaced intervals along the lengths thereof and operative to fixedly displace said surfacing member relative to said rigid member to thereby impart a predetermined configuration to said surfacing member for providing a corresponding contour to the surface of said concrete.

9. An apparatus for surfacing a longitudinal section of freshly laid concrete,v unbounded by side forms and which has already been generally leveled by conventional means, said apparatus comprising:

a frame adapted to span said section of concrete;

meanssupportingsaid frame for location of said frame above the surface of said section of concrete and including rolling means at the sides of said frame, said rolling means including ground engaging portions depending below said frame for traction upon irregular contours of the ground or other-supporting surface laterally outwardly of said concrete whereby,

said frame is transportable in a longitudinal direction over said concrete and out of contact therewith;

an elongated surfacing member suspended from said frame for spanning the width of said concrete, said member having a curved lower surface for surfacing said concrete;

side forms at opposite sides of said frame for slipping engagement with the vertical side edges of said concrete;

a plurality of sets of support means for said side forms,

each said set including a pair of elongated telescoping support elements, one of said elements being car ried by said frame for pivotal movement about a longitudinally extending, horizontal axis and the other of said elements being fixedly attached to an associated one of said side forms;

a pulley mounted to each of said one of said elements above the pivot point thereof;

a plurality of cables for raising said side forms, each of said cables being attached to one of said side forms and trained through the associated said pulley;

means for pulling on said cables to initially telescope said telescoping support elements and thereby raise said side forms, and thereafter pivot said support elements and said side forms outwardly of said frame; and

means suspending said member from said frame in diagonal orientation relative to the direction of transport of said frame for dragging engagement with the surface of said concrete during said transport of said frame whereby bumps and similar irregularities in said concrete are smoothed by said member and any excess concrete is conveyed diagonally along the length of said member, said last-mentioned means including separate connecting elements coupled to opposite extremities of said member, respectively, and operable independently of each other, said connecting elements being characterized by flexibility whereby said member derives its vertical orientation and support solely from floating on said concrete, and whereby purely vertical movements of said frame and differential vertical movements of said frame resulting from lateral tipping thereof are isolated from said member, and whereby vertical movements of any of said connecting elements are isolated from any other of said connecting elements during a surfacing operation.

References Cited by the Examiner UNITED STATES PATENTS 1,457,299 6/ 1923 Carr 94-45 1,588,837 6/1926 Jones 94-44 1,736,413 11/1929 Lichtenberg 94-45 X 2,194,754 3/1940 Johnson 94-44 2,203,529 6/ 1940 Harvey 94-45 2,245,426 6/ 1941 Baker 94-46 2,251,095 6/1941 Wood 94-46 2,252,188 8/ 1941 Krehbiel 94-45 2,333,041 10/ 1943 Poulter 94-45 2,426,703 9/ 1947 Millikin et al 94-45 2,605,682 8/1952 Sarosdy 94-45 3,015,257 1/1962 Apel et a1. 94-45 OTHER REFERENCES Rex Slip Form Paver, Chain Belt Company Bulletin 58,169, filed in Patent Ofiice May 23, 1960, 6 pages.

CHARLES E. OCONNELL, Primary Examiner.

JACOB L. NACKENOFF, Examiner. 

1. AN APPARATUS FOR SURFACING A LONGITUDINAL SECTION OF FRESHLY LAID CONCRETE UNBOUNDED BY SIDE FORMS AND WHICH HAS ALREADY BEEN GENERALLY LEVELED BY CONVENTIONAL MEANS, SAID APPARATUS COMPRISING: A FRAME ADAPTED TO SPAN SAID SECTION OF CONCRETE; MEANS SUPPORTING SAID FRAME FOR LOCATION OF SAID FRAME ABOVE THE SURFACE OF SAID SECTION OF CONCRETE AND INCLUDING ROLLING MEANS AT THE SIDES OF SAID FRAME, SAID ROLLING MEANS INCLUDING GROUND ENGAGING PORTIONS DEPENDING BELOW SAID FRAME FOR TRACTION UPON IRREGULAR CONTOURS OF THE GROUND OR OTHER SUPPORTING SURFACE LATERALLY OUTWARDLY OF SAID CONCRETE WHEREBY SAID FRAME IS TRANSPORTABLE IN A LONGITUDINAL DIRECTION OVER SAID CONCRETE AND OUT OF CONTACT THEREWITH; AN ELONGATED SURFACING MEMBER SUSPENDED FROM SAID FRAME FOR SPANNING THE WIDTH OF SAID CONCRETE, SAID MEMBER HAVING A CURVED LOWER SURFACE FOR SURFACING SAID CONCRETE; AND MEANS SUSPENDING SAID MEMBER FROM SAID FRAME IN DIAGONAL ORIENTATION RELATIVE TO THE DIRECTION OF TRANSPORT OF SAID FRAME FOR DRAGGING ENGAGEMENT WITH THE SURFACE OF SAID CONCRETE DURING SAID TRANSPORT OF SAID FRAME WHEREBY BUMPS AND SIMILAR IRREGULARITIES IN SAID CONCRETE ARE SMOOTHED BY SAID MEMBER AND ANY EXCESS CONCRETE IS CONVEYED DIAGONALLY ALONG THE LENGTH OF SAID MEMBER, SAID LAST-MENTIONED MEANS INCLUDING SEPARATE CONNECTING ELEMENTS COUPLED TO OPPOSITE EXTREMITIES OF SAID MEMBER, RESPECTIVELY, AND OPERABLE INDEPENDENTLY OF EACH OTHER, SAID CONNECTING ELEMENTS BEING CHARACTERIZED BY FLEXIBILITY WHEREBY SAID MEMBER DERIVES ITS VERTICAL ORIENTATION AND SUPPORT SOLELY FROM FLOATING ON SAID CONCRETE, AND WHEREBY PURELY VERTICAL MOVEMENTS OF SAID FRAME AND DIFFERENTIAL VERTICAL MOVEMENTS OF SAID FRAME RESULTING FROM LATERAL TIPPING THEREOF ARE ISOLATED FROM SAID MEMBER AND WHEREBY VERTICAL MOVEMENTS OF ANY OF SAID CONNECTING ELEMENTS ARE ISOLATED FROM ANY OTHER OF SAID CONNECTING ELEMENTS DURING A SURFACING OPERATION. 